Patent GB-1434611-A (GB)
Title: Drive-transmission and punch unit for a punch press
IPC: B30B1/26
Filed: 1973-04-30
Abstract: 1434611 Punching; nibbling U S AMADA Ltd 30 April 1973 [5 May 1972] 20404/73 Heading B3W A drive transmission and punch unit for a punch press comprises a frame, a twist member 32 having upwardly projecting equispaced cam waves (36) (portion 36r shown in Fig. 4) on its upper face, at least two balls 28 resting on the cam waves, means, such as a gear 21, for rolling the balls over the cam waves while preventing upward movement of the balls whereby the member 32 is moved down every time the balls pass over the waves, a punch-carrying ram coupled to biasing means 57 for biasing the ram and the member 32 upwardly, and a clutch 43 for engaging and disengaging the balls from the rolling means. As shown, Fig. 11, the gear 21 is driven from the flywheel 12 of the punch press and has an annular groove in its lower face for, preferably three, balls 28. A second track for the balls, in the upper face of the ring 32 includes cam waves (36), (Fig. 8, not shown). The ram 56 is mounted on a housing 258 which is fixed to the ring 32 and is formed with a slot 202 in which a clutch ring 43 engages. The clutch ring is rotatable between a punching position, in which a dog 44 engages a step ST on the housing to cause the ring 32 to hold the balls 28 against the track in the gear 21, and a neutral position in which the dog 44 engages a step NE and lowers the housing and the ring 32 and thus disengages the balls 28 from the gear track. The ram is returned by the spring 57. The drive transmission unit may have a second set of balls 78 and co-operable cam waves 86, on a ring 54, Fig. 4, greater in number than the waves (36), to allow punching at a faster speed or nibbling. A clutch ring 46 with external dogs 47 meshing with the internal dogs 44 on the clutch ring 43 selectively couples a drive ring 58 with the balls 78. The dogs are located in notches 102, Fig. 9, in a ram guide sleeve 50 carrying pins 34 on which the ring 32 is reciprocable and the vertically-fixed clutch ring 43 is rotatable between a punching, neutral and faster punching or nibbling position ST, NE, NI respectively by a fluid actuator 115. With the ring 43 in the neutral position shown in Fig. 9, the dogs 44 and 47 are resting on steps NE and NI respectively in the notches 102, the sleeve 50 and thus the ring 32 being held just too low for the gear 21 to engage the balls 28 and a shoulder 52 on the sleeve 50 engaging the ring 54 to hold the balls 78 away from the drive ring 58. With the ring 43 in the punching position, the dogs 44 rest on the steps ST in notches 102 which are sufficiently lower than the steps NE to allow the ring 32 to press the balls 28 against the gear 21. In order to rotate the ring 43 to the nibbling or fast punching position shown in Fig. 4, the sleeve 50 first has to be lowered by movement of the balls 28 into engagement with the crests of the cam waves (36). This moves the clutch ring 46 below the ring 43 so that the dogs 44 can be moved above the dogs 47 resting on the steps NI in notches 102, Fig. 4. The ring 32 is thus lowered to disengage the balls 28 from the gear 21 and the ring 46 pushes the drive ring 58 downwardly, overcoming a spring 90 and allowing the ram return spring 57 to raise the ring 54 to hold the balls 78 against the drive ring 58. Adjustable spring brakes (110) and (114) (Fig. 1, not shown) bear on ball cages 38, 92 respectively to bring the balls to rest when the clutch mechanism is placed in the neutral position. The upward movement of the ring 32 is damped by air trapped between shoulders 68 and 69 on the ring and a fixed part 16 of the unit respectively.